1. Field of the Invention
The present invention relates to a solid material gasification method and apparatus as well as a thin film formation process and apparatus. The present invention can be advantageously used for CVD and other thin film formation processes, and is therefore useful in the production of semiconductor devices and so forth.
2. Description of the Related Art
One of the production steps of semiconductor devices includes a process for forming a thin film by gasifying a solid raw material, and such processes are commonly known and widely used. In addition, known examples of such thin film formation processes include sputtering, vacuum vapor deposition and chemical vapor deposition (CVD). In such thin film formation processes, the following types of processes are generally used to gasify solid raw materials. For example, in the case of forming a thin film of an oxide of an organometallic compound on the surface of a substrate by CVD, after sublimating the solid raw material (powder), the generated reactive gas is introduced into a CVD device and adhered onto a treated substrate (see, Japanese Unexamined Patent Publication (Kokai) No. 5-311446). In addition, after dissolving the solid raw material in a solvent such as tetrahydrofuran (THF), butyl acetate or hexane, the resulting solution is vaporized and introduced into a CVD device where it can also be adhered to a treated substrate (see, Japanese Unexamined Patent Publication (Kokai) Nos. 7-76778 and 10-298762).
However, in these conventional thin film formation processes, several important problems remain unresolved. For example, in the case of carrying out thin film formation using a sublimation process, as the solid raw material must be maintained in a heated state at all times, it is difficult to avoid deterioration of the composition and properties of the thin film attributable to decomposition of the raw material. In addition, in the case of a using a solvent vaporization process, there is the problem of the generation of residue and particles caused by separation and vaporization of solvent. Moreover, there are also cases in which film deposition is inhibited during the early stages of thin film formation due to the reducing action of the solvent.